Revision 499ebb3ab5ea4207950fc95acf102b8f58add1c5 authored by Maysam Yabandeh on 24 June 2017, 21:06:43 UTC, committed by Facebook Github Bot on 24 June 2017, 21:11:29 UTC
Summary: Throughput: 46k tps in our sysbench settings (filling the details later) The idea is to have the simplest change that gives us a reasonable boost in 2PC throughput. Major design changes: 1. The WAL file internal buffer is not flushed after each write. Instead it is flushed before critical operations (WAL copy via fs) or when FlushWAL is called by MySQL. Flushing the WAL buffer is also protected via mutex_. 2. Use two sequence numbers: last seq, and last seq for write. Last seq is the last visible sequence number for reads. Last seq for write is the next sequence number that should be used to write to WAL/memtable. This allows to have a memtable write be in parallel to WAL writes. 3. BatchGroup is not used for writes. This means that we can have parallel writers which changes a major assumption in the code base. To accommodate for that i) allow only 1 WriteImpl that intends to write to memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes come via group commit phase which is serial anyway, ii) make all the parts in the code base that assumed to be the only writer (via EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are protected via a stat_mutex_. Note: the first commit has the approach figured out but is not clean. Submitting the PR anyway to get the early feedback on the approach. If we are ok with the approach I will go ahead with this updates: 0) Rebase with Yi's pipelining changes 1) Currently batching is disabled by default to make sure that it will be consistent with all unit tests. Will make this optional via a config. 2) A couple of unit tests are disabled. They need to be updated with the serial commit of 2PC taken into account. 3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires releasing mutex_ beforehand (the same way EnterUnbatched does). This needs to be cleaned up. Closes https://github.com/facebook/rocksdb/pull/2345 Differential Revision: D5210732 Pulled By: maysamyabandeh fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4
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_config.yml
# Site settings
permalink: /blog/:year/:month/:day/:title.html
title: RocksDB
tagline: A persistent key-value store for fast storage environments
description: >
RocksDB is an embeddable persistent key-value store for fast storage.
fbappid: "1615782811974223"
gacode: "UA-49459723-1"
# baseurl determines the subpath of your site. For example if you're using an
# organisation.github.io/reponame/ basic site URL, then baseurl would be set
# as "/reponame" but leave blank if you have a top-level domain URL as it is
# now set to "" by default as discussed in:
# http://jekyllrb.com/news/2016/10/06/jekyll-3-3-is-here/
baseurl: ""
# the base hostname & protocol for your site
# If baseurl is set, then the absolute url for your site would be url/baseurl
# This was also be set to the right thing automatically for local development
# https://github.com/blog/2277-what-s-new-in-github-pages-with-jekyll-3-3
# http://jekyllrb.com/news/2016/10/06/jekyll-3-3-is-here/
url: "http://rocksdb.org"
# Note: There are new filters in Jekyll 3.3 to help with absolute and relative urls
# absolute_url
# relative_url
# So you will see these used throughout the Jekyll code in this template.
# no more need for | prepend: site.url | prepend: site.baseurl
# http://jekyllrb.com/news/2016/10/06/jekyll-3-3-is-here/
#https://github.com/blog/2277-what-s-new-in-github-pages-with-jekyll-3-3
# The GitHub repo for your project
ghrepo: "facebook/rocksdb"
# Use these color settings to determine your colour scheme for the site.
color:
# primary should be a vivid color that reflects the project's brand
primary: "#2a2a2a"
# secondary should be a subtle light or dark color used on page backgrounds
secondary: "#f9f9f9"
# Use the following to specify whether the previous two colours are 'light'
# or 'dark' and therefore what colors can be overlaid on them
primary-overlay: "dark"
secondary-overlay: "light"
#Uncomment this if you want to enable Algolia doc search with your own values
#searchconfig:
# apikey: ""
# indexname: ""
# Blog posts are builtin to Jekyll by default, with the `_posts` directory.
# Here you can specify other types of documentation. The names here are `docs`
# and `top-level`. This means their content will be in `_docs` and `_top-level`.
# The permalink format is also given.
# http://ben.balter.com/2015/02/20/jekyll-collections/
collections:
docs:
output: true
permalink: /docs/:name/
top-level:
output: true
permalink: :name.html
# DO NOT ADJUST BELOW THIS LINE UNLESS YOU KNOW WHAT YOU ARE CHANGING
markdown: kramdown
kramdown:
input: GFM
syntax_highlighter: rouge
syntax_highlighter_opts:
css_class: 'rougeHighlight'
span:
line_numbers: false
block:
line_numbers: true
start_line: 1
sass:
style: :compressed
redcarpet:
extensions: [with_toc_data]
gems:
- jekyll-redirect-from
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